<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>丝带徽章</title>
</head>

<body>
    <!--
        作者：放弃懒惰
        链接：https://www.zhihu.com/question/40149352/answer/3123033666
        来源：知乎
        著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。
    -->
    <div class="badge-ribbon"></div>
    <style>
        .badge-ribbon {
            position: relative;
            display: block;
            height: 100px;
            width: 100px;
            background-color: rgb(212, 9, 9);
            border-radius: 50%;
        }

        .badge-ribbon:before,
        .badge-ribbon:after {
            position: absolute;
            top: 70px;
            left: -10px;
            content: "";
            border-right: 40px solid transparent;
            border-bottom: 70px solid rgb(13, 218, 40);
            border-left: 40px solid transparent;
            transform: rotate(-140deg);
            z-index: -1;
        }

        .badge-ribbon:after {
            right: -10px;
            left: auto;
            transform: rotate(140deg);
        }
    </style>
</body>

</html>